Pumpkin Pie Tunnel Cake

2-3/4 cups self-rising flour
1/2 cup oat bran
1-1/4 cups firmly packed brown sugar
1 cup pumpkin
1-1/2 teaspoon pumpkin pie spice
1/2 teaspoon maple flavoring
1 egg
1/4 cup vegetable oil
1 teaspoon vegetable oil
2 egg whites
1-1/3 cups buttermilk
2 teaspoons vanilla extract
1/2 cup confectioners' sugar
2 teaspoons milk
1/2 teaspoon pumpkin pie spice

In a small bowl, combine flour and oat bran. In a small bowl, combine 1/4 cup brown sugar, pumpkin, pumpkin pie spice, maple flavoring, and egg; mix well.

Preheat oven to 350�F. Spray a 10-inch Bundt pan with non-stick vegetable spray.
In a large mixing bowl, combine remaining brown sugar and oil; beat until well blended. Add egg whites; beat thoroughly. Add flour mixture alternately with buttermilk; beating well after each addition. Stir in vanilla. Remove 2 cups of the batter; set aside. Pour remaining batter in prepared Bundt pan. Spoon pumpkin mixture evenly over center of batter to form a ring. Spoon reserved batter over the top.

Bake for 50 minutes or until a tester inserted in the center comes out clean. Cool in pan for 20 minutes. Remove from pan; cool completely on a wire rack.

In a small bowl, combine confectioners' sugar, milk, and pumpkin pie spice; stir until smooth. Drizzle over cake.